What are illegal surrender, yin-yang insurance policy, retention premium and sitting premium?

"Yin-Yang bill" refers to insurance business bills, whose stubs are inconsistent with the accounting records in the retained data of company insurance bills, or whose stubs are consistent with the accounting records, but their accounting records are inconsistent with the payment to insurance customers. The difference, that is, the concealed and intercepted premium income, also mostly flows into the "small treasury".